Abstract: A press brake for bending a work sheet wherein an upper tool holder is mounted at a lower end of a ram to mount an upper tool and a bending angle of a work sheet is determined by three points of spaced shoulders of a lower tool and a lower tool bottom. The press brake includes a group of pins as pressure transmission members, arranged at symmetrical positions from a machine center line in the upper tool. A space is provided between the tops of some of the pins and a press block. A series of spacers is mounted on a chain mechanism for putting the spacers into and out from the space between the press block and the pins. The effective length of the upper tool is automatically changed corresponding to the bending length of the work sheets so as to achieve an efficient bending of various length work sheets and preventing unequal bending.

Abstract: A device for measuring a bending angle of a bent sheet material including a bending angle detector including first and second links arranged symmetrically relative to each other and pivotally connected with each other at one end thereof, a support mechanism for supporting the angle detector on a displaceable ram of the sheet bending press and for displacing the angle detector into an angular space defined by the bending angle of the bent sheet material, and a mechanism for biasing the first and second links into a surface contact with side surfaces of the bent sheet material defining the bending angle.

Abstract: A bending machine having a plurality of reversible dies mounted on the lower end of a ram. A reversibly supporting shaft is laterally installed at the rear side of the ram, and a reversing lever is mounted on the reversibly supporting shaft. The reversible dies are removably mounted on the ends of the reversing lever to be readily exchanged from the upper die to the goose-neck die or vice versa.

Abstract: An apparatus for adjusting the tool length of a bending machine comprises a ram having a lower end, a top tool body mounted on the lower end of the ram, a bottom tool mounted below the top tool body, a top tool including a pair of central dies mounted longitudinally movably on the lower end of the ram, a plurality of upper split dies arranged outside the central dies and mounted reversibly to the upper die row, a plurality of thin upper dies inserted reversibly between the central dies and being thinner than the upper split die, and upper corner dies arranged on both left and right ends of the upper split die, a shift mechanism for sliding the central dies reversely at the central portion of the lower portion of the ram, a drive mechanism for sliding the upper corner dies to the longitudinally symmetrical positions of the lower portion of the ram, shafts pivotably disposed at the back of the central dies and upper corner dies, a plurality of the upper split dies wedged to the shafts and reversed in pivoting o

Abstract: This invention relates to a forming machine which is composed of several types of split dies in an upper die. The length of the upper die is adjusted by changing the combination of the split dies. The upper die assembly has an upper die body mounted on the lower end of a ram. A group of upper split dies are slideably inserted laterally of the die and in the lower portion of the upper die body. A number of upper thin dies are inversely mounted at the center of the upper split die group. A select finger driving mechanism is provided at the front of the upper die body to slide the upper split dies in the lateral direction of the die. An inverting mechanism is provided at the rear of the upper die body to invert the desired number of the upper thin dies and locate them between the split dies to form a die of the desired bending length.